//     Zepto.js
//     (c) 2010-2012 Thomas Fuchs
//     Zepto.js may be freely distributed under the MIT license.

;(function($){
    var touch = {},
        touchTimeout, tapTimeout, swipeTimeout,
        longTapDelay = 750, longTapTimeout

    function parentIfText(node) {
        return 'tagName' in node ? node : node.parentNode
    }

    function swipeDirection(x1, x2, y1, y2) {
        var xDelta = Math.abs(x1 - x2), yDelta = Math.abs(y1 - y2)
        return xDelta >= yDelta ? (x1 - x2 > 0 ? 'Left' : 'Right') : (y1 - y2 > 0 ? 'Up' : 'Down')
    }

    function longTap() {
        longTapTimeout = null
        if (touch.last) {
            touch.el.trigger('longTap')
            touch = {}
        }
    }

    function cancelLongTap() {
        if (longTapTimeout) clearTimeout(longTapTimeout)
        longTapTimeout = null
    }

    function cancelAll() {
        if (touchTimeout) clearTimeout(touchTimeout)
        if (tapTimeout) clearTimeout(tapTimeout)
        if (swipeTimeout) clearTimeout(swipeTimeout)
        if (longTapTimeout) clearTimeout(longTapTimeout)
        touchTimeout = tapTimeout = swipeTimeout = longTapTimeout = null
        touch = {}
    }

    $(document).ready(function(){
        var now, delta

        $(document.body)
            .bind('touchstart', function(e){
                now = Date.now()
                delta = now - (touch.last || now)
                touch.el = $(parentIfText(e.touches[0].target))
                touchTimeout && clearTimeout(touchTimeout)
                touch.x1 = e.touches[0].pageX
                touch.y1 = e.touches[0].pageY
                if (delta > 0 && delta <= 250) touch.isDoubleTap = true
                touch.last = now
                longTapTimeout = setTimeout(longTap, longTapDelay)
            })
            .bind('touchmove', function(e){
                cancelLongTap()
                touch.x2 = e.touches[0].pageX
                touch.y2 = e.touches[0].pageY
                if (Math.abs(touch.x1 - touch.x2) > 10)
                    e.preventDefault()
            })
            .bind('touchend', function(e){
                cancelLongTap()

                // swipe
                if ((touch.x2 && Math.abs(touch.x1 - touch.x2) > 30) ||
                    (touch.y2 && Math.abs(touch.y1 - touch.y2) > 30))

                    swipeTimeout = setTimeout(function() {
                        touch.el.trigger('swipe')
                        touch.el.trigger('swipe' + (swipeDirection(touch.x1, touch.x2, touch.y1, touch.y2)))
                        touch = {}
                    }, 0)

                // normal tap
                else if ('last' in touch)

                // delay by one tick so we can cancel the 'tap' event if 'scroll' fires
                // ('tap' fires before 'scroll')
                    tapTimeout = setTimeout(function() {

                        // trigger universal 'tap' with the option to cancelTouch()
                        // (cancelTouch cancels processing of single vs double taps for faster 'tap' response)
                        var event = $.Event('tap')
                        event.cancelTouch = cancelAll
                        touch.el.trigger(event)

                        // trigger double tap immediately
                        if (touch.isDoubleTap) {
                            touch.el.trigger('doubleTap')
                            touch = {}
                        }

                        // trigger single tap after 250ms of inactivity
                        else {
                            touchTimeout = setTimeout(function(){
                                touchTimeout = null
                                touch.el.trigger('singleTap')
                                touch = {}
                            }, 250)
                        }

                    }, 0)

            })
            .bind('touchcancel', cancelAll)

        $(window).bind('scroll', cancelAll)
    })

    ;['swipe', 'swipeLeft', 'swipeRight', 'swipeUp', 'swipeDown', 'doubleTap', 'tap', 'singleTap', 'longTap'].forEach(function(m){
        $.fn[m] = function(callback){ return this.bind(m, callback) }
    })
})(Zepto);